Telephone conversation timing means



May 6, 3952 F. KEssLER TELEPHONE CONVERSATION TIMING MEANS Filed DeC. 12, 1949 Patented May 6, 1952 OFFICE TELEPHONE CONVERSATION TIMING MEANS Frank Kessler, .Rochesten N. assignor tov Stromberg-Carlson Cqmpany, a` corporation of `New York Application December 12, 1949,'seria1N0. 132,616

My invention relates to automatic telephone systems and more particularly to conversation timing means for use in automatic telephone systems.

In automaticltelephone systems it is frequently desired to provide means for timing out certain calls a predetermined time after completion of a call. For example, it has been proposed to limit local calls to a predetermined length of conversation time but to permit toll calls to continue on an unlimited time basis.

It is an object of my invention to provide new and improved means for timing conversationin automatic telephone systems.

It is another object of my invention to provide new and improved conversation timing means which distinguishes betweenclasses ofcalls and times only a desired class or classes of calls.

It is another object of my invention .to provide conversation timing means utilizing` a vcontrol conductor not only to control the `timing function. but also to provide answering supervision.- -l

Other objects andA advantages of my invention will be better understood from the following description of my invention.

In accordance with the preferred-form of my invention, there is provided a conversation timing circuitcr adapter in a suitable location.: in a telephone. system as, lfor example,. between a finder-selector link and a connector in a step-bystep system wherein a finder is employed to eX- tend local as well as toll calls. A control ,conductor is extended from various line circuits and toll trunks to the connector. When a local .line initiates a call, upon answering by the called party, battery potential is applied to the conduc-V tor to initiate timing of the conversation period. On toll calls, however, the forwarding operator applies battery potential to the control conductor and means are provided to disable or prevent the operation of the timing means. Thus. means are provided for distinguishing between local and toll calls, although the principles of my invention are equally applicable to providing means for distinguishing between any diierent groups s claims.- (c1. `17e-7.1)

" diagram form atelephonevsystem embodying thel of 'lines or calls according to the presence or absence of potential on the incoming controlconfductor (with respect to the conversation timing circuit), land the timing means operates to initiate measurement of the durationof a call in dependenceupon a predetermined potential on the outgoing control lead.

For a detailed description of my invention, the following description may be read in connection with the drawings in which Fig. 1 shows in block principles of my inventon, Fig. 2 is a schematicdiagram of a conversation timing adapter or cir-L Cuit for use in the system depicted inFig. 1,and Fig. 3 illustrates the sequences of control potentials`for use in the circuit of Fig. 2.

Referring to Fig. 1, there is indicated a local line I which may be a private line or a party line. A party line having substations 2 and 3 isillustrated. Line I is connected to a suitale line circuit 4. Means are provided forv nding a calling line as, for example, a suitable finderv selector link indicated by the numeral 5 having a step-by-'step switch indicated by the numeral 5a adapted to successively test terminals in a suitable bank in search of a marked line.- Upon successfully finding the calling line, a-suitable step-bygstep switch indicated bythe numeral l' is caused to extend the call to a suitable connector 8 vand the latter through a suitable Astepby-step switch 8a extends the call to` line'circuit 9 and subscriber or substation I0. The details of the extensionof a call form no part of my; invention. Suitable circuits for such a system as that briey described above are disclosed in a copending application Serial No. 743,415, led April 23, 1947, now Patent No. 2,567,650, granted September 11, 1951, by Frank A. Morris and assigned to the same assignee as the present invention. l There is interposed between finder-selector link 5 and connector 8 a conversation timing circuit or adapter AII embodying the principles of my invention,.although the conversation timing circuit may be interposed at any desired point in the system.

Finder-selector link 5 is arranged to service not only local lines but also a predetermined.v mim ber of toll trunks and thus provides service-fortwo groups of lines, one comprising local lines- Whlch are to be limited with regard to length of conversation time and toll calls with respect to which unlimited conversation time is to be provided.

There is illustrated a toll line I2connectedto predetermined terminals in the nder bank by meansof a suitable trunk 4circuit I3. In the arf4 rangement illustrated in Fig. 1 thatl type oftrunk circuit is indicated in 'which an operator, in respons to a calling condition on toll line I2, forwards or extends the call over the toll line as by means of a suitable calling device suchvas a dial, not shown, but which, in a well-known manner, causes the operation of a suitable relay I5 to apply resistance battery to the HS or super- 3 visory lead I6 extending to the finder-selector link through contacts I5a.

Referring to connector 8, there is indicated a suitable relay- I'I arranged to be energized upon the answering of a call by subscriber I to apply battery through contacts I'Ia to the HS or supervisory conductor I8 back to the conversation timing adapter II. Suitable circuits for trunk I3 and connector 8 are illustrated in copending application Serial No. 139,632, led January 20, 1950, by William W. zPharis, and assigned to the same assignee as the present invention. Inasmuch as the details of these particular circuits form no direct part in my present invention, it is believed unnecessary to further illustrate or describe them. It may be mentioned, however, that relay I5 of trunk circuit I3 corresponds to relay SHI in the incoming toll repeater, Figs. 3 and 4, `of the aforementioned Pharis application, this last mentioned relay functioning to switch the HS lead to negative during each digit dialled and thus cause the connector to be switched from local to toll operation; and it may further be noted that relay I'I of connector 8 o'f the present application corresponds to relay AA, Fig. 5 in the connector of the Pharis application, this AA relay functioning upon answering by the called party to switch the HS lead to negative at the connector end and thus cause the incoming toll repeater to return answering supervision back over the toll trunk. These circuit functions are explained on pages 6, fl, -and 52 of the Pharis application.

Referring to Fig. 2, the operation of my conversation timing circuit is first described in connection with a local call with respect to which it is ldesired .to p-rovide conversation timing. It is assumed that a call from line I has been extended through connector 8 at which location ground is applied to back sleeve lead 26, as is more fully described in the above-identiedMorris application.

The appearance of ground on lead 23 energizes relay VS over an obvious circuit. The operation of relay S provides a local ground through make contacts 2I of relay S.

As previously described in a general manner, when the extended call is answered by subscriber I0, battery is connected to HS lead I8. In the following description, it is to be understood that the positive potential of the direct current sup- J ply is connected to ground and is hereafter referred toas ground and the negative terminal of the direct current source is hereafter referred toas battery." The appearance of battery on lead or conductor I8 is employed to energize relay HSE over a circuit extending from conductor I8 through break contacts 23 of relay HSL and break `contacts 24 of relay HSE to the lower winding of relay HSE. a

Relay HSE operates and locks up to the local ground through make contacts 25 of relay HSE; grounds the interrupter start lead IST through make contacts 26 of relay HSE (the interrupter constituting a source of control pulses, the time sequence of which is shown in Fig. 3; opens the above traced operating circuit to the lower winding of relay HSE at break contacts 24; transfers the Aback HS lead I8a from relay H SL to the forward or outgoing HS ,lead I8 at contacts 43, 2l of relay HSE so that a switch through connection free of all relay attachments in the adapter is now established between the two HS leads, this connection facilitating the transmission of signals over both HS leads in series if such signaling should be desired in this type of call; and connects timing lead TPI to the lower winding of relay TA through make contacts 28 of relay HSE and break contacts 29 of relay TB, lead TPI being connected to a suitable source of timing pulses and holding ground. Such a source is commonly a suitable multi-contact interrup-ter and any desired form may beused. In Fig. 2 there is shown a schematic arrangement represented as a plurality of switches disposed to be Aopened or closed, as the case may be, at suitable times to connect ground to the various leads as desired. For example, the switches can be operated by a vsuitable set of cams 48, these cams being mounted on a rotating shaft.

As a result of thelast-described circuit, referring tOFig. .3, at .time t1 the appearance of a pulse of ground potential on lead TPI causes energization of relay TA over the above-described circuit. Relay TA locks itself' to local ground over a `Ycircuit extending from the winding of relay '.TAzthrough make contacts 30 of relay TA, break :contacts 3I `of relay ATB and break contacts 32 of relay HSL. The operation of relay .TA also 4prepares a circuit for operating relay TB upon the receipt of the next ground pulse over lead TPZ at time t2 upon the next revolution of the interrupter. Upon the receipt of the vnext pulse TF2 at time t2 relay TB is operated kover a circuit including make contacts vS3 of relay TA and the lower winding of relay TB 4whichlocks up to local ground through make contacts 34 of relay TB.

Operation of relay TB V opens 4the energizing circuit Yfor relay .TA at :break'contacts 29 of .relay TB; Yconnects relay WT vto timing lead .CWT through make contacts v35 of .relay TB.; transfers the holding ground foi-relay TA ,from the localground togroundprovidedfromtiming lead HI asindicated in Fig. 3; and .transiersthe .con-v nection between front vsleeve 20 vand back sleeve 3'I at break .contact 38 `of relay TB to .a circuit including make contacts.39 .of relay TB and make contacts 4.0 of relay TA.

At time ta in the secondrevolution of the interrupter, Yground vis temporarily removed from timing ,lead HI .thereby dev-energizing .relay TA. and transferring :ground on sleeave conductors 2D and ,3] 'to vtiming .lead .H2 Iat break contacts 4l. At :time iti on Athe third revolution of the interrupter a pulse of ground is applied to lead CWT which results inthe energization of relay WT over the previously prepared circuit and the application of warning tone to tip lead T through make contacts '4I of relay WT and break contacts 42 of relay TA.

A second warning tone is transmitted at time t5.

Ground is temporarily removed from lead H2 at time te which removes the ground from they back sleeve lead 31 as well as front sleeve lead 20. The removal of ground from the sleeve leads causes de-energization of the circuits of both called and calling ends of the system in a manner well known to those skilled in the art,

It is to be understood that on local calls, there will be no HS or supervisory circuit required between line circuit 4 and adaptor or circuit II. In connection with toll calls, however, conductorv HS is extended between trunk I3 and nderselector link 5 as indicated by numeral IB and the HS or supervisory lead is extended from finder-selector link 5 to conversation timing circuit II as indicated by .numeral I8a.

As described above on the extension of a toll atomes call to the lnder-selector link 5 resistance battery'is applied to HSV lead I6 and, therefore, to HS lead la into timing apparatus II. The appearance of battery potential on lead I8a causes energization of relay HSL over a circuit extending from lead I8a through break contacts 43 of relay HSE and break contacts 44 of relay HSL to the lower winding of relay HSL. Relay HSL locks up to local ground through make contacts 45 of relay HSL; disconnects ground from the locking circuits of relays TA and TB at break contacts 32 of relay HSL; opens the above traced operating circuit to the lower winding of relay HSE at break contacts 23 of relay HSL; and transfers the back HS lead Ia from the lower winding of relay HSL to the front HS lead I3 at contacts 44, 46 of relay HSL so that a switch through connection free of all relay attachments" of the switch train may now be transmitted over both theseleads in series. More particularly, after the connection has been extended to connector 8, Fig. l, under the control of the dial pulses received over'toll line l2, Fig. l, the connector will be conditioned for toll operation in response tothe battery applied to the HS lead by relay l 5, Fig. l, during each digit dialled. Furthermore, the battery applied to the HS lead by relay I1 in the connector upon answering of the toll call by the called party will be returned over the switched through HS lead to trunk circuit I3 to cause this trunk circuit to reverse the current on the toll line and thereby given answering lsupervision to the toll operator.

-While Iehave shown and described a particular embodiment of my invention, it will be obv'iL 6 calls originating in said first group of calling lines, a first conductor extending from the called end of the extended call to said timing device, a' second conductor extending from the calling end of said extended call to said timing device, means at the called end of said first conductor effectiveA upon the anwering of an extended call to apply ousto those skilled in the art that changes and 5 modifications may be made without departing from my 4invention in its broader aspects. I,

thereforaaim in the appended claims to coverall i such changes and modifications as fall within the true spirit and scope of my invention.

What I claim is:

1. In a'telephone system, a first group of call# ing lines, a second group of calling lines, a called extending from the calling end of said extended call to said timing device, means at the called end of said first control lead for applying a control potential to said first control lead, means in said timing device responsive to said control potential if said call originated on a line in said rst group for closing a starting circuit for said timing device, means at the calling end of said second control lead for setting upa distinctive potential condition on said second lead if the call originated on a line in said second group. and means in said timing device controlledby said potential condition on said second control lead for rendering said timing device ineffective, said vlast mentioned means also being'A responsive to ,said potential condition on the second control lead for connecting said two con# trol leads to each other.

2. In a telephone system, a first group of calling lines, a second group of calling lines, a called line, means for extending a call from a calling conversation timing ldevice effective to time onl57 a control potential to said first conductor, means at the calling end of said second conductor eiective prior to the answering of an extended call for setting up a distinctive potential condition on said second conductor if said call originated in the second of said groups, said conversation timing device including a iirst relay and a second relay nor-v mally connected to said first and second .conduce tors respectively, said first relay being responsive to said control potential on the first conductor-in the case of a call originating in said first group for causing a starting circuit for said timing device to be closed and said second relay beingA operative under the control of said potential condition on the second conductor to render said rst relay ineffective, said second relay also being responsive to said potential condition on the second conductor for causing said conductors to be connected to each other free of relay attachments in said device.

3. In a telephone system, a first group of calling lines, a second group of calling lines, a called line, means for extending a call from a calling line in one of said groups to said called line, .a

conversation timing device, a first control lead extending from the called end of the extended call to said timing device, a second control lead extending from the calling end of said extended call to said timing device, means at the called end of said first control lead for applying a control potential to said first control lead, relay means in said timing device responsive vto said control potential if said ycall originated on a line` in said first group for closing a starting circuit for said timing device, means at the calling end of said second control lead for setting up a distinctive potential condition on said second lead if the call originated on a line in said second group, and relay -means in said timing device controlled by said potential condition on said second control lead for rendering said timing device ineffective, said lastmentioned relaymeans also being responsive to"'saidpotential condition on the second control lea'd for connecting said control leads to each other free of all relay atatachments in said device.

4. In a telephone system,A a first group of calling lines, a second group of calling lines, a called line, means for extending a call from a calling line in one of said groups to said called line, a conversation timing device, a first control lead extending from the called end of the extended call to said timing device, a second control lead extending from the calling end of said extended call to said timing devicemeans at" the called end of said first control lead Aeffective .upon -the answering of an extended call to apply a control potential to said first control lead, means in said timing device responsive to ysaid control potentiai if said can originated in the first of said groups for closing a starting circuit for said timing device, means at the calling end of said second control lead eiective prior to the answering of an extended call if said call originated in the second of said groups for applying a control potential to said lead, and means in said tim-- ing device controlled by said potential on the secr ond control lead for rendering said timing device secondcontrolleadjor connecting :said two control leads to each-other. l =j=5. Inra telephone system, a first group of callinglinespa second group of calling lines, a called line, means for extending 'a call from a calling line in loneof said groups to said called line, a conversation .timing device effective to time only callsloriginating in said first group of calling lines, atrst conductor extending from the kcalled end of theextended call to said timing device, a secund .conductor extending from thecalling end of said extended-.call to said timing device, means aftiythecalled end of said first conductor effective uponzthe .answering cf an extended call to apply acontrolpotential to said rst conductor, means atY the calling end of said second conductor .effective priorto the answering of an vextended call for settingv up -a distinctive potential 'condition on.

said second conductor if said call Voriginated in the second of said groups, said conversation timing-device includinga rst relay and a second relaynormally connectedto said rst and second conductors respectively, said first relay vbeing responsive to 'said control potential on the rst conductor in the case of a call originating in said rst group for causing a starting circuit forsaid timing device to be closed and also responsive to said control potential on the rst conductor for causing said conductors to be connected to each other free of relay attachments in said device, and said second relay being opera tive under the control of said potential condition on the second conductor to render said first rela-yineiective.

.A .6. In1a ,telephone system, a flrst group of callying lines, a second group of calling lines, va called line, means for extending a lcall from a calling .line in one of said groups to said called line,-a conversation timing device effective to time only calls originating in said first 'group vof calling lines, a rst conductor extendingfroin the called end of the extended -call to said timing device, -a fsecond conductor extending from the calling end of said vextended call to said timing device, means `'at the called end of said first conductor effective upon the answering of an extended call -to apply-a control potential to said rst conductor, 'means at the calling end of said vsecond conl 'ductor eiective prior to the answering of an extended call for setting up a distinctive potential condition on said second conductor if said call originated in the second of said groups, said conversation timing device including a rst relay l and-a second relay, said firstrelay having a winding `normally connected to said first .conductor under the control of said second relay, said second relay having a winding normally connected '.to,said.'sec ond conductor under the control of -said Vfirst relay, said rst relay being responsive tto said control potential on the first conductor in'the case of a call originating in said first group for causing a 'starting .circuit for Said timing device to bejclosed land said conductors to be connected to'each other free of relay attachments in said device, and said second relay being operative under the control of said potential condition on the lsecond conductor to render said first Arelay ineffectiveand cause vsaid'conductor's to be 'connected to each other free of relay attachments 7.`In ia telephone'system, a rst group of calling lines, a second group of calling lines, a called Aline, means for extending a call from a calling line'inione yof said groups to said called line, a

conversation timing device eiective lto time only calls `originating in said first lgroup of calling lines, a rstconductor extending ,from thecalled end of the extended call to ,said timing device, a second conductor extending from the 4calling end of said extended call to said timing device, means at the called end of said rst conductor eiective upon the answering of an extended call to apply a control potential to said first conductor, means at the calling end of said second conductor effective prior to the answering of .an extended call for setting up a distinctive potential condition on Asaid second conductor .ifsaidcall originated inthe second of `said groups,lsaid conversation timing device including a iirst relay/,and a second relay, said rst relayhaving a winding normally connected to said rst conductor under the control of said second relay, said second .relay having a winding normally ,connected to .said second vconductor under the control of said rst relay, said first relay being responsive to said control potential on the first conductor in the case of a call originating in said first group for closing a starting circuit for said timing device, closing a locking circuit for itself, disconnecting both of said relay windings from said conductors and connecting both said conductors to each other, and said second relay being operative under the control of said potential condition on the second conductor to disconnect said winding of the first relay from said first conductor for rendering said relay eiective, close a locking circuit for said second relay, disconnect said winding .of the second relay from said second conductor and connect said conductors to each other. y

8. In a telephone system, a first .circuitterminating a calling local line, a second circuit terminating a calling toll line, `a called line, aconnector,having access to said calledline, a conversation timing device eiicctive to time only calls from said second calling circuit, a switch train for extending a call from one of said two calling circuits through said conversation timing device to said connector, a first control lead extending from said connector to said timing device, a second control lead extending from said second calling circuit to said timing device, means in lsaid connector effective to apply a control potential to said first control lead upon answering of said call over said called line, means in said second circuit effective if the call originated from said toll line to apply a control potential to said sec-'- ond control lead prior to answering, said timing device including relay means responsive to said control potential on the first control lead if the call originated from said local line for closing a starting circuit for said timing device and `relay means responsive to said control potential on the second control lead for rendering said first mentioned relay means ineffective and causing said control leads to be switched through free of all relay attachments in said timing device.

FRANK ICESSLER.

REFERENCES CITED The following references are of record in the iile of this patent:

. UNITED STATES PATENTS Number .Name Date Y' 1,694,170 Friendly Dec. 4, 1928 1,696,275 Johnson et al Dec, 25, 1928 2,025,880 McDavitt Dec. 31, 1935 2,427,000 Hovland Sept. 9, 1947 2,490,221 Lomax Dec. 6, 1949 

